The present invention relates to a facsimile apparatus, printer, digital copier or similar image forming apparatus.
A facsimile apparatus, for example, includes a plotter or image forming means for recording image data on a paper or similar recording medium. For this purpose, the facsimile apparatus needs a page memory capable of accommodating at least one page of image data. It is a common practice with the facsimile apparatus to transfer image data from the page memory to the plotter without the intermediary of a CPU (Central Processing Unit), i.e., by a DMA (Direct Memory Access) system. The DMA system allows the CPU to efficiently execute processing other than one for the data transfer from the page memory to the plotter and thereby increases the image forming speed. The page memory is, in many cases, implemented by a DRAM (Dynamic Random Access Memory) which is most desirable from the cost standpoint.
To further increase the image forming speed, it is necessary to increase the DMA transfer rate of the image data from the page memory to the plotter. In practice, however, the image data transfer rate has heretofore been limited due to the capacity of the page memory.
It is therefore an object of the present invention to provide an image forming apparatus capable of increasing the DMA transfer rate of image data from a page memory or DRAM to image forming means.
An image forming apparatus of the present invention includes an image forming section, a page memory for storing at least one page of image data to be transferred to the image forming section, and a DMA controller. The page memory is implemented by a DRAM. The DMA controller continuously transfers, in response to a single DMA request received from the image forming section, a plurality of words of image data with the same row address from the DRAM to the image forming section at a time by DMA transfer.